Animal Science Terms - N

National Research Council (NRC): scientific body in the U.S. that has regularly published nutrient requirements for animals based on the latest available research

Near-infrared analysis (NIRA): laboratory analysis of feeds that uses a specific wavelength of near infrared light to estimate nutrient content of feeds based on computerized calibrations of nutrient composition of feedstuffs; a lower-cost analysis compared with traditional wet chemistry. It is dependent on correct calibration to specific feeds for accurate analysis 

Near-infrared spectroscopy (NIRS): see Near-infrared analysis 

Necropsy: examine an animal after death to determine the cause of death

Neonatal: relating to newborn animals

Net energy (NE): amount of feed energy actually available for animal maintenance and production, representing the energy fraction in a feed left after fecal, urinary, gas and heat losses are deducted from the gross energy value of a feed. Net energy can be further partitioned into the net energy necessary for maintenance, growth and lactation

Neutral detergent fibre (NDF): insoluble fraction containing all plant cell wall components left after boiling a feed sample in a neutral detergent solution. NDF is of low digestibility but can be broken down somewhat by the digestive tract microorganisms. NDF value is used to predict ruminant feed intake

Niacin: water-soluble B vitamin involved in the metabolism of carbohydrates, lipids and proteins. It is essential in monogastric diets but not for ruminants and non-ruminant herbivores. Niacin has a beneficial role in controlling energy use and ketosis in dairy cattle, especially in early lactation

Nitrate percent (NO3%): minor component of the nitrogen-containing fraction of feed. Nitrate levels can increase in a crop that has been subjected to drought (specifically after a rainfall), hail, frost or high levels of nitrogen fertilization. Feeds having greater than 1% nitrate can be toxic to ruminants

Nitrogen: nonmetallic element that makes up about 78 percent of the atmosphere by volume, occurring as a colorless, odorless gas. It is a component of all proteins, making it essential for life, and it is also found in various minerals. Nitrogen is used to make ammonia, nitric acid, TNT and fertilizers. Symbol N

Non-essential amino acids: amino acids that can be synthesized by the animal 

Non-fibre carbohydrate: see Non-structural carbohydrate

Non-protein nitrogen (NPN): nitrogen based feed ingredient not derived from true protein, but usable by rumen microbes to build microbial protein with enough energy, (e.g., urea, biuret, and ammonia)

Non-structural carbohydrate (NSC): simple carbohydrates, such as starches and sugars, stored inside the cell that serve as a cellular energy source. Non-structural carbohydrates are rapidly and easily digested by the animal

Nutrient: substance that provides nourishment for growth or metabolism. One of six classes of chemical compounds having specific functions in the nutritive support of animal life. Animals mainly obtain nutrients from ingested food

Nutrient allowances: recommendations for the nutrient amounts necessary for maintenance, growth, gestation, lactation or performance that include a safety margin to account for variability in feeds and animals (e.g., environment, health, storage losses)

Nutrient Management Plan: planning resource that defines the nutrient needs of crops and the amount, sources, placement and timing of fertilizer applications to maximize nutrient uptake of the crop and improve yields. Implementation of nutrient management plans should protect the environment, maintain crop productivity and increase profitability

Nutrient requirements: minimum amounts of nutrients (energy, protein, minerals and vitamins) necessary to meet an animal's needs for maintenance, growth, health, reproduction, lactation, or work; does not include a margin of error in ration formulation 

Nutrition: 1. process by which living organisms obtain food and use it for growth, metabolism and repair 2. study of nutrients, determining what nutrients are required, what levels of nutrients are necessary for various levels of productivity, and how to provide those nutrients 



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